Enable PDF plugin for iframes within the print preview dialog.

chrome/browser/printing/print_view_manager.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROME_BROWSER_PRINTING_PRINT_VIEW_MANAGER_H_
 #define CHROME_BROWSER_PRINTING_PRINT_VIEW_MANAGER_H_
 
 #include "chrome/browser/printing/print_view_manager_base.h"
 #include "content/public/browser/web_contents_user_data.h"
 
@@ skipping 38 matching lines @@
 
   // Sets |observer| as the current PrintViewManagerObserver. Pass in NULL to
   // remove the current observer. |observer| may always be NULL, but |observer_|
   // must be NULL if |observer| is non-NULL.
   void set_observer(PrintViewManagerObserver* observer);
 
   // content::WebContentsObserver implementation.
   bool OnMessageReceived(const IPC::Message& message) override;
 
   // content::WebContentsObserver implementation.
+  void RenderFrameCreated(content::RenderFrameHost* render_frame_host) override;
+
+  // content::WebContentsObserver implementation.
   // Terminates or cancels the print job if one was pending.
   void RenderProcessGone(base::TerminationStatus status) override;
 
  private:
   explicit PrintViewManager(content::WebContents* web_contents);
   friend class content::WebContentsUserData<PrintViewManager>;
 
   enum PrintPreviewState {
     NOT_PREVIEWING,
     USER_INITIATED_PREVIEW,
@@ skipping 15 matching lines @@
 
   // Keeps track of the pending callback during scripted print preview.
   content::RenderProcessHost* scripted_print_preview_rph_;
 
   DISALLOW_COPY_AND_ASSIGN(PrintViewManager);
 };
 
 }  // namespace printing
 
 #endif  // CHROME_BROWSER_PRINTING_PRINT_VIEW_MANAGER_H_